Radio receiver antenna switching device



June 9, 1959 BERLINGHOFF 2,890,450

4 RADIO RECEIVER ANTENNA SWITCHING DEVICE 2 Sheets-Sheet 1 Filed Dec.11, 1953 INVENTOR FRANZ BERLIWG/IQF/T BY fifi I AGENT June 9, 1959 F.BERLINGHOFF RADIO RECEIVER ANTENNA SWITCHING DEVICE Filed Dec. 11, 19532 Sheets-Sheet 2 Rica/Va? A Ill/II INVENTOR FRANZ BEfll/NGHOFfi' AGENTUnited States Patent RADIO RECEIVER ANTENNA SWITCHING DEVICE FranzBerlingh'olf, Hamburg, Germany, assignor, by mesne assignments, to NorthAmerican Philips Company, Inc, New York, N.Y., a corporation of DelawareApplication December 11, 1953, Serial No. 397,655

Claims priority, application Germany March 17, 1953 6 Claims. (Cl.343-100) The present invention relates to a radio receiver antennaswitching device. More particularly, the invention relates to a radioreceiver of the type comprising a directional antenna and anomnidirectional antenna and to a switching device therefor.

It has proved advantageous to operate radio apparatus with a directionalantenna, preferably in the form of a ferrite-rod antenna. This is due tothe fact that particularly the frequencies of the medium wave-range areoccupied by stations which, although they may be widely remote from oneanother geographically, nevertheless tend to interfere with each otherespecially in intermediate ranges in the evening hours. The use of apreferably rotary directional antenna often permits an interferingstation to be strongly suppressed so that the desired station is betterreceived.

When searching for a station with the directional antenna operated, itwill often be impossible to receive stations in the direction of minimumreception of the antenna. A technically unskilled listener will not beable to trace a desired station or will be able to do so only withdifficulty. This is annoying and may even give rise to completedissatisfaction with the directional antenna and the receivingapparatus.

The disadvantages discussed are obviated and full use is made of theadvantages accruing from a receiver with a directional antenna if,according to the invention, an omnidirectional antenna is operated fortracing a station on tuning (choice of station).

The omnidirectional antenna, may be for example, a supply line antenna,an auxiliary antenna incorporated in the receiver, an indoor antenna oran outdoor antenna. To operate the omnidirectional antenna it is notabsolutely necessary to disconnect the directional antenna. With theomnidirectional antenna on it will often do to connect the directionalantenna, for' example capacitatively, to the grid of the input tube, theenergy thus received from a station in the minimum direction of thedirectional antenna being sufficient to make it perceptible. Hence, itis not necessary to obtain an exactly omnidirectional receivingcharacteristic with additional operation of the omnidirectional antenna.That is, it is not necessary to receive equally well from alldirections, it being sufficient to avoid a marked minimum.

When disconnecting the omnidirectional antenna a tuned directionalantenna may remain operative as an input circuit and, for example, atapping or an additional winding on the directional antenna, permitsimpedance matching of the omnidirectional antenna.

A rotary ferrite-rod antenna is usually incorporated in a radio receiveras a directional antenna. The advantages accruing from the inventionare, however, also obtained with an apparatus which comprises a fixeddirectional antenna in its cabinet and consequently must be turned as awhole for direction finding, for example, in the case of portablereceivers.

Changing over of the antenna is preferably effected automatically byoperating a member for tuning and/or ice adjusting the directionalantenna, the tuning member preferably being stopped with operativedirectional antenna. The stopping may, for example, result from brakinga flywheel or the like.

The force exerted in the stopped condition on the tunmg member (tuningknob) on operating the latter may serve to change over to theomnidirectional antenna and to release. The release is preferablyeffected by axial displacement of the tuning member.

In order that the invention may be readily carried into effect, it willnow be described with reference to the accompanying drawing, in which:

Flg. 1 is a schematic diagram of an embodiment of the antenna switchingdevice of the present invention; and

Fig. 2 is a schematic diagram of another embodiment. of the antennaswitching device of the presentinvention.

Fig. 1 shows a device for a radio receiver with a directional antenna.According to the invention an omnidirectional antenna is connectedautomatically by operatmg the tuning knob, and a separate switch, forexample a press-button, is used for changing over from omnidirectionalto directional reception. The. directional antenna connected to thetuning member is stopped by means of braking a flywheel or the like.Fig. 1 illustrates the condition in which the omnidirectional antenna(not shown) is connected via soldered joints 2 by means of adiagrammatically represented switch 1 and the tuning element, forexample a rotary capacitor, is freely controllable by means of a knob 3and a cord .4. A radio receiver R has a rotatable ferromagnetic roddirectional antenna D and an omnidirectional antenna 0 which isconnected automatically to the tuning mechanism of the receiver. Theknob 3 is mounted on a solid shaft 5 which passes through a hollow shaft6. A spring 7 cm gages at one end a ring 8 resting on a pin 9 fitted inthe shaft 5, and at its other end the hollow shaft 6 via another ring10. A stud 12 fitted secured to the shaft 5 is guided in a substantiallyV-shaped slot 11 and maintained at the point of the V by the force ofspring 7 in the rest position and also during normal tuning. Besides thecord 4 the hollow shaft 6 carries a flywheel 13. By means of aball-bearing 14 provided close to the flywheel said shaft is mounted tothe cabinet so as to have the weight of the flywheel mainly supported bysaid ball bearing. At the end carrying the knob 3, the shaft 5 is guidedin a hole of the front plate 15 or the like.

After adjustment to the desired station by means of the omnidirectionalantenna, the directional antenna is connected for direct communication.To this end a press-button 21 is operated (Fig. 1) by pushing a rod 22"against the force of a spring 23 resting at one end on the plate 24 andat its other end on a ring 25 and a pin 26 secured to the rod 22. Thetoggle lever 27 is then carried along with the pin 29, secured to rod22, by means of the eye 28, the spring-loaded tipping device 30 finallybeing tripped and the upper end of the lever 27, which end is furnishedwith a brake lining 31, engaging the flywheel 13. Due to the shape ofthe eye 28 the tilting of the lever 27 is abruptly effectedindependently of the degree or rate of pressing the button 21.

After the button 21 has been fully depressed, the lug 32 snaps under theprojection 33 of the stopping lever 34 which is pivotally supported inits fulcrum where it is subjected to the action of a spiral spring 35.The antenna switch 1 is operated by pushing the rod 22. Said rod alsopasses through a chassis plate 36 or the like.

After the aforesaid operations are executed, the directional antenna'isoperative and the flywheel of the tuning member 5, 6 has been braked viathe lever 27 with lining 31, thus incapacitating the tuning element, forexample, a rotary capacitor, during any rotation of the directionalantenna.

' When a different station is chosen the tuning knob 3 is turned, asusual, in one or in the other direction. Since the hollow shaft 6 isstopped as a result of the braking of the wheel13, the stud 12 movesinto the V-shaped slot 11, thus-axially displacing the rotating shaft inthe direction of its flywheel end. In this manner, the lever 34 isactuated and the rod 22 is released. The rod 22 moves downwardly andcarries along the lever 27 by means of the pin 29, thus releasing thetuning member to permit free tuning. The rod 22 in its downward movementalong with the press-button 21 also operates the switch 1 which, inturn, connects the omnidirectional antenna.

In the device described, axial displacement occurs automatically onoperating the mechanical tuning member in the stopped condition, so thatthe antenna is changed over and the wheel 13 is no longer braked. Thetipping device 30 causes the engagement and lifting of the brake lever27, 31 to occur abruptly, thus avoiding in operativeness of tuning andensuring reliable operation of the device.

Fig. 2 shows a device for a receiver comprising a directional antenna,in which on the one hand engagement .of the omnidirectional antenna iseffected automatically, on operating the tuning member and on the otherhand changing over to the directional reception is efiectedautomatically on operating the member for rotating the directionalantenna.

At the right in Fig. 2, similarly to Fig. 1, the mechanical controlmember 3, 5, 6 for a tuning element (for example, a rotary capacitor,not shown) is depicted whose rotation is transmitted by means of a cord4. At the left a similar contact member 3, 5, 6' is shown, thuspermitting a directional receiving antenna (not shown) to be turned bymeans of a cord 4'. Secured to the hollow shafts 6 and 6' are brakewheels 13 and 13, respectively, of which at least one may be a flywheel.By means of the spring-loaded tipping device 40 a brake lever 41 withbrake lining 42 is urged against the wheel 13 or the wheel 13'. By meansof the mechanism 7, 11, 12 and 7, 11, 12, respectively, described withreference to Fig. 1, for the axial displacement, the brake lever 41 isactuated via intermediate levers 43 and 43' to stop each time theinoperative adjusting devices 6, 4 and 6', 4, respectively.

In the condition shown in the drawing, the omnidirectional antenna isconnected by a diagrammatically represented antenna switch 44, thedirectional antenna being connected in the opposite condition.

Instead of using the mechanical changing over device shown in thedrawing it is alternatively possible to employ contact-controlled relaysor other electromagnetic or electronic switching elements. This may beparticularly advisable in transmission systems where, for example, theoperating member (knob) and the directional antenna are spaced widelyapart or heavy and bulky antenna systems must be rotated which whileadopting the aforesaid principle, may not only be used for directionalreception but also for directional transmission. In this instance, forexample an omnidirectional signal may be transmitted by means of anomnidirectional antenna, the intelligence traflic proper then takingplace via a directive connection to secure a higher degree of freedom.

While the invention has been described by means of specific examples andin specific embodiments, I do not wish to be limited thereto, forobvious modifications will occur to those skilled in the art withoutdeparting from the spirit and scope of the invention.

What is claimed is:

1. A switching device for selectively connecting an omnidirectionalantenna. to a radio receiver connected to a directional antenna andhaving tuning means for selecting a desired frequency, comprising meansoperated by said tuning means for automatically connecting saidomnidirectional antenna to said radio receiver and means fordisconnecting said omnidirectional antenna from said radio receiver.

2. A switching device for selectively connecting an omnidirectionalantenna to a radio receiver connected to a directional antenna andhaving tuning means for selecting a desired frequency, comprising meansoperated by said tuning means for automatically connecting saidomnidirectional antenna to said radio receiver, means for disconnectingsaid omnidirectional antenna from said radio receiver, and meansoperated by said disconnecting means for stopping said tuning means whensaid disconnecting means is operated to disconnect said omnidirectionalantenna from said radio receiver.

3. A switching device for selectively connecting an omnidirectionalantenna to a radio receiver connected to a directional antenna andhaving tuning means for selecting adesired frequency, said tuning meanscomprising a rotary member having a flywheel affixed thereto, comprisingmeans operated by said tuning means for automatically connecting saidomnidirectional antenna to said radio receiver, means for disconnectingsaidomnidirectional antenna from said radio receiver, and braking meansadapted to coact with said flywheel and operated by said disconnectingmeans to contact the said flywheel when said disconnecting means isoperated to disconnect said omnidirectional antenna from said radioreceiver.

4. A switching device for selectively connecting an omnidirectionalantenna to a radio receiver connected to a directional antenna andhaving tuning means for selecting a desired frequency, said tuning meanscomprising a rotary member, comprising means operated by said tuningmeans for automatically connecting said omnidirectional antenna to saidradio receiver, means for disconnecting said omnidirectional antennafrom said radio receiver, and means operated by said disconnecting meansfor stopping said tuning means when said disconnecting means is operatedto disconnect said omnidirectional antenna from said radio receiver,said rotary member being mounted in cooperating relationship with saidmeans for stopping said tuning means in a manner whereby a force appliedto said rotary member in the stopped condition of said tuning meanscauses said stopping means to become inoperative and operates said meansfor connecting said omnidirectional antenna to said radio receiver.

5. A switching device for selectively connecting an omnidirectionalantenna to a radio receiver connected to a directional antenna andhaving tuning means for selecting a desired frequency, comprising meansoperated by said tuning means forautomatically connecting saidomnidirectional antenna to said radio receiver and pushbutton switchingmeans for disconnecting said omnidirectional antenna from said radioreceiver.

6. A switching device for selectively connecting an omnidirectionalantenna to a radio receiver connected to a directional antenna andhaving means for rotating said directional antenna and tuning means forselecting a desired frequency, comprising means operated by said tuningmeans for automatically connecting said omnidirectional antenna to saidradio receiver and means operated by said directional antenna rotatingmeans for automatically disconnecting said omnidirectional antenna fromsaid radio receiver.

References Cited in the file of this patent UNITED STATES PATENTS

